Evaluating CERES-Maize for reduction in plant population or leaf area during the growing season

Abstract

A crop model able to simulate the effects of a reduction in plant population and/or leaf area would be useful to estimate yield losses from biotic (e.g. pathogens and arthropods) and abiotic (e.g. hail) stresses. The purpose of this study was to evaluate the response of a structured version of CERES-Maize (V 1·0) to reduction in plant population or leaf area at various growth stages. Simulation results showed that the model was not able to predict a grain yield plateau at high plant populations and overpredicted grain yield by as much as 16% when the plant population was 6·5 plants m −2. When plant population was reduced below 5·6 plants m −2, CERES-Maize underpredicted yield, but accurately predicted the trends observed in the field data. In response to reduction in leaf area, the model over-predicted kernel number and underpredicted kernel weight except at 100% reduction in leaf area during vegetative growth. In this situation, the model was not able to simulate the growth of the remaining leaves in the whorl and produce a yield. These results were based on independent data sets from two locations in the Corn Belt. To address these problems in the model, the relationship between grain yield and plant population, the redistribution of carbon during vegetative growth after reduction in leaf area, and the prediction of kernel number should be investigated.